Varying-speed mechanism.



l Patan ted Nov. 20, I900; -H. B. MITCHELL. VARYING SPEED MECHANISM.

[Application filed Mar. 2, 1900.]

2 Sheetsr-Shbef I.

(No Modal.)

; No. 662,380.. Patented Nov.20, I900.

H. B. MITCHELL. VABYING SPEED MECHANISM.

.(Application filed Mar. 2, 1900.) (No Model.)

2 She'efs-Sheet 2.

"m: uonms PETERS ca, PNOTO-LITNO., wAsHmmun. n c.

llrrnn Smarts arnnr Fries.

HUGH BURT MITCHELL, OF CANTON, OHIO, ASSIGNOR-TO ANDREI/V M. MOCARTY, ALBERT HOEFFER, AND ADAM O. MGDOVELL, OF SAME PLACE.

VARYlNG-SPEED MECHANISM.

SPECIFICATION forming part Of Letters Patent N 0. 662,380, dated November 20, 1900.

Application filed March 2, 1900. Serial No. 7,069. (No model.)

To all whom it may concern.-

Be it known that I, HUGH BURT MrroHnLL, a citizen of the United States, residing at Canton, in the county of Stark and State of Ohio, have invented certain new and useful Improvements in Varying-Speed Mechanism; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the annexed drawings, making a part of this specification, and to the figures of reference marked thereon, in Which- Figure 1 is aperspective view showing the different parts properly assembled. Fig. 2 is a view showing the hemisphere and cylinder in proper relative positions. Fig. 3 is a sectional view of the hemisphere, also a transverse section of the rack-bar cylinder, showing a portion of the base. Fig. 4c is a top view. Fig. 5 is a side elevation. Fig. 6 is an end View.

The present invention has relation to varying-speed mechanism more especially designed for use in dental engines; and it consists in the different parts and combination of parts hereinafter described, and particularly pointed out in the claims.

Similar numerals of reference indicate corresponding parts in all the figures of the drawings.

In the accompanying drawings, 1 represents the bracket or shelf, which is securely connected at any desired point, either to the wall or to a frame, as may be desired. Upon the front portion of the bracket or shelf 1 are located the integral posts 2, which are preferably located as illustrated in the drawings. To the posts 2 are connected the spring-standards 3, said spring-standards being held in proper position bymeansofthe clamping-bolts 4 or their equivalents. To the top or upper ends of the standards 3 is connected the bar 5, which bar is held in proper relative position with reference to the standards 3 by means of the set-screws 6 or their equivalents. Upon the bar 5 is loosely mounted the cylinder 7, which cylinder is formed of sufficient length to regulate the degree of speed and at the same time reverse the direction of motion, as hereinafter described.

From the bracket 1 extends the arm 8,

l which arm is preferably formed integral with the bracket 1; but it will be understood that the arm may be made separate and attached in any convenient and well-known manner. To the arm 8 is journaled the shaft or rod 9, to the top or upper portion of which is connected the toothed segment 10, and above said toothed segment is connected the arm 11, said arm being extended upward, and to its upper end is connected the rod 12, upon which rod is loosely mounted the hub 13 of the hemisphere 14:. At or about the equatorial portion of the hemisphere 14 is formed the annular groove 15, which groove receives the driving-belt 16, which driving-belt is properly connected to the motor-wheel 17.

In the drawings I have illustrated a portion of an electric motor, which is the most con venient motor to use; but itwill be understood that any kind of a motor may be employed.

Upon the bar 5 are located the suspendingrods 18, said suspending-rods being so connected to the bar that they will slide back and forth with the cylinder 7, as hereinafter described. To the bottom or lower ends of the suspending-rods 1.8 is connected the rack-bar 19, which rack-bar is so located that it will engage the teeth of the segment 10.

For the purpose of holding the rack bar 19 in proper contact with the segment the spring 20 is provided, which spring is so located that it will press against the rear edge of the rack-bar 19, said spring being connected at one end to the block 21 or its equivalent, said block being securely connected to the bracket or shelf 1, or it may be formed integral therewith, or the spring may be attached to any other part of the bracket, as the only object is to provide an attaching-point for the spring.

\rVhen it is desired to impart motion to the cylinder 7 by means of the hemisphere 14, said hemisphere is brought to a point where its axis is at an angle other than a right angle to the cylinder 7, by which movement the contact'point of the hemisphere against the cylinder is removedfrom the pole of said hemisphere. It will also be understood that as the hemisphere is turned, so as to bring the contact-point toward the equatorial line of said hemisphere, the speed of the cylinder will be increased in proportion to the distance between the pole and the equatorial linethat is to say, the greatest speed is produced when the nearest approach is made to the equator of the hemisphere-and when the contactpoint between the cylinder and hemisphere is at the pole of the hemisphere no rotary mo tion will be imparted to the cylinder 7, but said cylinder will be brought to a stop.

It will be understood that when the hemisphere is rotated horizontally in one direction a certain rotary motion will be imparted to the cylinder 7, and when said hemisphere is turned in the opposite direction a reverse motion will be given to the cylinder 7 after the contact-point has passed the pole of the hemisphere, the direction or motion of the hemisphere being the same in both instances.

For the purpose of causing the cylinder 7 to be moved longitudinally with the horizontal movement of the hemisphere the toothed segment is securely connected to the shaft 9 and meshes with the rack-bar 19, and as the rack-bar 19 is moved back and forth the cylinder 7 will be carried with said rack-bar upon the rod 5 by means of the suspending-rods 18, said suspending-rods being located at the ends of the cylinder 7 and in close contact therewith.

For the purpose of increasing the frictional contact between the surface of the hemisphere 14 and the surface of the cylinder 7 said parts may be covered With rubber or like'material, by which arrangement there can be no lost motion between the hemisphere 14 and the cylinder 7.

For the purpose of adjusting the frictional contact between the hemisphere and cylinder the arms 3 are formed of spring material and their upper ends brought toward or from the hemisphere 14 by means of the adjustingscrews 22, said adjusting-screws being seated in the posts 2.

For the purpose of imparting motion to the dental engine proper the cylinder 7 is provided with a groove 23, which groove may be located as illustrated in the drawings, or it may be located at any other point, as the only object of the groove is to receive the drivingbelt 24.

For the purpose of providing a means for locating the motor-wheel 17" directly below the groove 15, formed in the hemisphere, the shaft 9 is bent or curved, as illustrated in the drawings, by which arrangement the axis of power-Wheel 17 can be brought in alinement with that of the shaft 9, thereby permitting the hemisphere to be turned or moved with the'shaft 9 without danger'of disconnecting the belt 16. inasmuch as the shaft 9 does not make a complete revolution the bend 25 will not interfere With the rocking movement of said shaft. It will be understood that as the shaft 9 is rocked it will also rock the arm 11, said arm It will also be understood that being connectedto the upper end (if the shaft 9, by which movement a swinging or oscillating movement is imparted to the rod 12 and carries with it the hemisphere 14.

For the purpose of regulating the speed or reversing the motion the pulley 26 isprovided, around which pulley is located the belt 27, which belt may lead to any desired connection, as the only object is to provide some means for rocking the shaft 9 by means of the pulley 26 and the belt 27.

The bottom or lower end of the shaft 9 is journaled to the block 28 or its equivalent, which block is connected to the floor or to any other desired object.

For the purpose of properly holding the hemisphere 14 in proper relative position the rod or bolt 12 is provided with the head 14*, which head is countersunk into the hemisphere at its pole, and for the purpose of preventing any grinding the cover 15 is removed from the hemisphere proper directly over the head.

It will be understood that by locating the groove 23 in the cylinder 7 said groove will come directly opposite the head 14: when said parts are brought into the position illustrated in Fig. 1. a

For the purpose of changing the contactpoints of the hemisphere against the cylinder said cylinder is slidably mounted upon its rod or bar, by which arrangement no grinding or slipping is permitted at the time the point of contact is varied between the pole of the hemisphere and its equatorial line.

By providing the sliding cylinder the surface of the hemisphere and the cylinder can be provided with a cover of sufficient elasticity to give the desired amount of friction without great pressure, thereby providing a means for easily regulating the speed.

Having fully described my invention, what I claim as new, and desire to scan re by Letters Patent, is v 1. The combination of an oscillating hemisphere rotatable upon its axis, a reciprocating cylinder held in frictional contact against the surface of the hemisphere, means for oscillating the hemisphere and means for imparting a reciprocating movement to the cylinder, substantially as and for the purpose specified.

2. In a speed-varying device, a shaft or rod, a cylinder slidably mounted thereon,suspending-bars connected to the rod carrying the cylinder and located at either end thereof, a rack-bar carried by the suspending-rods, a toothed segment located to mesh with the rack-bar, a hemisphere a rock-shaft carrying an arm, a hemisphere-rod mounted upon the arm carried by the rock-shaft and means for imparting rotary mot-ion to the hemisphere, substantially as and for the purpgse specified.

3. In a speed-varying device, an oscillating hemisphere and a sliding cylinder located in frictional contact face to face with each other,

the upper ends of said posts, a cylinder slidably mounted upon the bar, an oscillating hemisphere bearing against the face of the cylinder and means for adjusting the frictional contact between the contact-faces of the hemisphere and cylinder, substantially as and for the purpose specified.

In testimony that I claim the above I have hereunto subscribed my name in the presence of two witnesses.

HUGH BURT MITCHELL.

Witnesses:

J. A. JEFFERs, F. W. BOND. 

